Special Staining Special stains allow us to make special structures visible that might not otherwise be visible using other staining techniques. 4 Special stains:

1. Flagella staining – simply know and be able to recognize a flagella stain as one with flagella in it! Know the flagellar arrangements.

2. Negative staining – Capsules do not stain well, but we can use the negative staining technique in which the background is stained a dark color, and the bacterial cell is counterstained, but the capsule stays clear. India ink or nigrosin is used for the background, and safranin is used to stain the cell. Negative Stain (Nigrosin) Negative Stain (India Ink)

3. Endospore staining – Endospores are difficult to stain due to their impenetrable nature. We use steam and time as a means to stain endospores.

Endospore Staining: *Lay slides on steaming grate bacteria side up* 1. Flood slide with malachite green (primary stain) 2. Allow stain to steam into endospores for 12 minutes. 3. Remove slide and rinse with water at sink 4. Flood slide with safranin (counter stain) for 1 minute 5. Rinse with water 6. Blot dry with bibulous paper

4. Acid Fast Staining (Ziehl Neelson Staining Technique) - Used to stain bacteria from the genus Mycobacterium i.e. Mycobacterium tuberculosis - Special staining procedure is needed due to the thick waxy outer covering of Mycolic Acid that cannot be stained using other staining techniques.